Clinical UM Guideline

This document addresses colonoscopy, an endoscopic procedure which allows direct visual inspection of the entire colon and rectum. Additionally, biopsy or excision of polyps or other abnormalities are possible during the colonoscopy procedure.

Colonoscopy must be distinguished from CT colonography, an imaging procedure that provides indirect visualization of the colon and rectum using CT scans. This document does not address CT Colonography.

Note: The parenthetical numbers in the Clinical Indications section refer to the source documents cited in the References section below.

Medically Necessary:

1. Screening Colonoscopy in Average Risk Populations (that is, asymptomatic individuals without specific risk factors including no personal history of adenomas, sessile serrated polyps [SSPs], colorectal cancer, inflammatory bowel disease, or cystic fibrosis, and no family history of colorectal cancer).
   1. Colonoscopy to detect colorectal cancer and adenomatous polyps is appropriate:
      1. Beginning at age 45 years; (13, 22, 29, 38) and
      2. Every 10 years thereafter. (11)
         or
   2. For individuals with a personal history of a hyperplastic, non-sessile serrated polyp (non-SSP) removed at colonoscopy, measuring less than 1 cm and in the rectum and sigmoid only, the first follow up colonoscopy is appropriate in 10 years. (15, 18, 21)
      or
   3. For individuals with a personal history of a negative stool-based test:
      1. If prior screening was conducted using a guaiac-based or an immunohistochemical test, re-screening may be performed with colonoscopy in 1 year; (21) or
      2. If prior screening test was conducted using Cologuard, re-screening may be performed using colonoscopy in 3 years.                            
2. Surveillance Colonoscopy in At-Risk Populations
   1. Individuals who have a personal history of a positive stool based (guaiac-based, immunohistochemical or Cologuard fecal DNA) test and the confirmatory colonoscopy was positive for cancer or pre-cancerous polyp, surveillance may be appropriate based on clinical findings. (21)
   2. Colorectal Cancer: For those with a personal history of colorectal cancer that has been resected with curative intent, colonoscopy is appropriate for any of the following:
      1. To rule out synchronous neoplasms; no less than 3 months after cancer resection, if no unresectable metastases are found during surgery. Alternatively, colonoscopy can be performed intraoperatively, or preoperatively if non-obstructing tumor; (2, 14, 15, 21, 29) or
      2. 1 year after the curative resection if a complete preoperative colonoscopy was performed, or no less than 3 months after curative resection if there was no or incomplete preoperative colonoscopy, or 1 year following the colonoscopy that was performed to clear the colon of synchronous disease; (2, 14, 15, 21, 30) or
      3. No less than 2 years after the “1 year” follow up colonoscopy, if examination was normal. (2, 3, 14, 15, 21, 30)
      4. For this specific group, colonoscopy may be repeated thereafter at an interval of no less than 3 years, based on previous findings. (2, 3, 14, 15, 21, 30)
   3. Adenomatous Polyps or Sessile Serrated Polyps (SSP): Those who have a personal history of one or more adenomatous polyps or SSPs removed at colonoscopy are managed according to the findings (that is, considering number of polyps and pathology). Colonoscopy may be appropriate in any of the following:
      1. For those with 1 or 2 small (less than 1 cm) tubular adenomas or SSPs without cytologic dysplasia, the first follow-up colonoscopy is appropriate in no less than 5 years; (2, 11, 15, 18, 21) or
      2. For individuals with a history of any of the following, the first follow-up colonoscopy is appropriate 3 years after the initial polypectomy:
         1. 3 to 9 adenomatous polyps and/or SSPs; (11, 21, 22) or
         2. Any adenoma or SSP greater than or equal to 1 cm; (11, 21) or
         3. Any adenoma with villous or tubulovillous features; (11, 21) or
         4. Any adenoma with high-grade dysplasia; (11, 21) or
         5. Any SSP with cytologic dysplasia (2, 11, 15, 18, 21)
            or
      3. For those with 10 or more adenomas on a single examination, the first follow-up colonoscopy is appropriate less than 3 years after the initial polypectomy based on clinical judgment; (2, 15, 18, 22) or
      4. For those with a malignant adenoma (with invasive cancer), a large sessile adenoma, or an incomplete colonoscopy, a short interval between the initial and follow up colonoscopy is appropriate based on clinical judgment; or
      5. For those with sessile adenomas that are removed piecemeal, the first follow-up colonoscopy is appropriate at no less than 2 months to verify complete removal. (2, 15, 21, 26)
         Note: The timing of the subsequent colonoscopy is dependent upon the pathology and the number of adenomas detected at the "follow-up colonoscopy.” For example, if the first "follow-up colonoscopy" is normal or only 1 or 2 small (less than 1cm) tubular adenomas are found, then the next colonoscopy can be in 10 years. (21)
   4. Serrated Polyposis Syndrome (SPS)
      1. For individuals with serrated polyposis syndrome, colonoscopy is appropriate as follows:
         1. Colonoscopy with polypectomy until all polyps greater than or equal to 5 mm are removed; (22) and
         2. Then colonoscopy no less than every year depending on the number and size of polyps. (22).
   5. Colonic Adenomatous Polyposis of Unknown Etiology: For individuals with a personal history of colonic adenomatous polyposis of unknown etiology (without known APC or biallelic MUTYH mutations), colonoscopy is appropriate as follows: 
      1. For those with a personal history of more than 10 but less than 100 small (less than 1 cm) adenomas which are manageable by colonoscopy and polypectomy, colonoscopy is appropriate no less than every year. Repeat colonoscopy performed at a shorter interval is appropriate if residual polyps are present. (22)
   6. Inflammatory Bowel Disease (chronic ulcerative colitis or Crohn's colitis) and related conditions:
      1. For individuals with inflammatory bowel disease, colonoscopy is appropriate as follows:
         1. Surveillance colonoscopy beginning no less than 8 years after onset of colitis, and repeated no less than 1 year thereafter; (2, 8, 15, 21) or
         2. For those with primary sclerosing cholangitis (PSC), begin surveillance colonoscopy at the time of diagnosis and then undergo yearly colonoscopy thereafter; (8, 21, 31) or
         3. When individual has undergone endoscopic resection of a visible dysplastic lesion, the next surveillance colonoscopy should occur at 3–6 months. (17, 20)
   7. Cystic Fibrosis: Research has shown an increased risk of colorectal cancer in individuals with cystic fibrosis. Studies have also demonstrated that individuals with cystic fibrosis who underwent transplant had a higher incidence of digestive tract tumors:
      1. For individuals with a personal history of cystic fibrosis and no history of solid organ transplant:
         1. Colonoscopy beginning at age 40; (22) and
         2. Rescreening in 5 years if normal; (22) or
         3. Repeat in 3 years if colonoscopy reports adenomatous polyps; (22)
            or
      2. For individuals with a personal history of cystic fibrosis and a solid organ transplant:
         1. Colonoscopy beginning at age 30 years; (22) or within 2 years of the transplantation; and
         2. Rescreening in 5 years if normal; or
         3. Repeat in 3 years if colonoscopy reports adenomatous polyps.
   8. Increased Risk Based on Personal History of Childhood, Adolescent and Young Adult Cancer:
      1. For individuals with a personal history of childhood, or adolescent and young adult cancer (age 15-39 years at the time of initial cancer diagnosis) treated with chemotherapy (without radiation therapy): 
         1. Colonoscopy beginning at age 35; (22) or
         2. 10 years after age of chemotherapy, (whichever comes first); (22) and
         3. For this specific group, colonoscopy may be repeated every 5 years. (22)
            or
      2. For individuals with a personal history of childhood, adolescent or young adult cancer treated with radiation of the abdominopelvic field, (that is, abdomen, pelvis, spine [lumbar, sacral, whole] or total body irradiation [TBI]), (with or without chemotherapy);
         1. Colonoscopy beginning at age 30; (22, 44) or
         2. 5 years after treatment (whichever occurs last); (22, 44) and
         3. For this specific group, colonoscopy may be repeated every 5 years. (22, 44)
3. Screening Colonoscopy in Higher Risk Populations
   1. Family History of Colorectal Cancer or Adenomas: The vast majority of those with increased risk are in this category. Screening colonoscopy is appropriate for a person with a family history indicating any of the following:
      1. One first degree relative (parent, sibling or child) with colorectal cancer diagnosed at any age; (2, 18, 22, 29)
         1. Colonoscopy beginning at age 40; (2, 18, 22, 29) or
         2. Colonoscopy beginning at an age 10 years younger than the age at diagnosis of the youngest affected relative, whichever comes first. (2, 18, 22, 29) and
         3. For this specific group, colonoscopy may be repeated no less than every 3 years depending on findings. (2, 18, 22)
            or
      2. One second and one third-degree relative with colorectal cancer at any age;
         1. Colonoscopy beginning at age 45; (22) and
         2. For this specific group, colonoscopy may be repeated every 10 years, depending on findings. (22)
            or  
      3. One first-degree relative with confirmed advanced adenoma(s) (for example, high-grade dysplasia, greater than or equal to 1 cm, villous or tubulovillous histology, traditional serrated adenoma [TSA]) or advanced SSPs/SSLs (greater than or equal to 1 cm, dysplasia) at any age:
         1. Colonoscopy beginning at age 40 or at age of onset of adenoma in affected relative, whichever is first. (21, 22) and
         2. For this specific group, colonoscopy may be repeated no less than every 5 years, or if positive, repeat per colonoscopy findings. (21, 22)
            Note: Increased numbers of affected first-degree relatives influences risk much more than affected second-degree relatives or third-degree relatives. However, when combined with a positive first-degree family history, a positive second- and third-degree family history can significantly increase risk. (21)
   2. Familial adenomatous polyposis (FAP): In this autosomal dominant syndrome, affected persons have a risk of colorectal cancer approaching 100%. The average age of adenoma appearance is 16, and the average age of colon cancer is 39. Most affected individuals develop more than 100 adenomas. Thus early and regular screening is appropriate for any of the following. (2)
      1. For those with a genetic diagnosis of FAP, or who are at risk for this diagnosis but genetic testing has not been done or is not feasible:
         1. Offer genetic counseling, as specific genetic abnormalities can be identified in approximately 80% of affected individuals. This can then be used to screen other family members; (29) and
         2. Annual sigmoidoscopy or colonoscopy beginning at an age no less than 10 years: (2, 22) and
            1. With an appropriately timed colectomy indicated when polyps develop; (2, 22, 29) or
            2. If no polyps develop, annual sigmoidoscopy to age 40 then no less than every 3 years thereafter. (2)
               or
      2. For the family members of those with FAP who do not have specific genetic evidence or clinical manifestations of the disease:
         1. In the older, unscreened relatives of a person newly diagnosed with FAP, colonoscopy is appropriate for the first screening examination; (23) and
         2. Annual screening sigmoidoscopy until age 40 if no polyps develop; (23) and
         3. An appropriately timed colectomy indicated if polyps develop. (8, 23)
            Note: While the above is applicable to individuals with FAP and their families, there are variants of this syndrome, attenuated adenomatous polyposis coli (AAPC) (also referred to as attenuated FAP) and MYH-associated polyposis. The genetic mutations leading to these variants differ from that in the typical FAP individual. These variants are associated with a variable number of adenomas (usually 20 to 100), a tendency toward right sided lesions, and an age of onset of colorectal cancer that is approximately 10 years later than for others with FAP. As with FAP, genetic counseling for these individuals and early and regular screening is warranted. It is recommended that this screening begin in the late teens or early 20s, depending on the age of polyp expression in the family. (35)
   3. Lynch Syndrome, also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC): For individuals with a genetic or clinical diagnosis of, or who are at increased risk for Lynch Syndrome, colonoscopy is appropriate as follows:
      1. For individuals who are MLH1, MSH2 and EPCAM mutation carriers:
         1. No less than every year beginning at an age no less than 20 years old or no less than 2 years prior to the earliest colon cancer in a first-degree relative if it is diagnosed before age 25; (10, 23) or
      2. For individuals who are MSH6 and PMS2 mutation carriers:
         1. No less than every year beginning at an age no less than 25years old or no less than 2 years prior to the earliest colon cancer in a first-degree relative if it is diagnosed before age 30. (23)
   4. Serrated Polyposis Syndrome (SPS)
      1. For individuals with a family history of serrated polyposis syndrome, colonoscopy is appropriate in the first-degree relative of the individual with serrated polyposis syndrome at the earliest of the following: 
         1. Age 40; (23) or
         2. Same age as the youngest diagnosis of serrated polyposis if uncomplicated by cancer; (23) or
         3. Ten years earlier than earliest diagnosis in family of colorectal cancer complicating serrated polyposis. (23)
            1. Following baseline exam, repeat colonoscopy every 5 years if no polyps are found; (23) or
            2. If proximal serrated polyps or multiple adenomas are found, consider colonoscopy no less than every year. (23)
   5. Colonic Adenomatous Polyposis of Unknown Etiology: For individuals with a family history of colonic adenomatous polyposis of unknown etiology (without known APC or biallelic MUTYH mutations), colonoscopy is appropriate as follows: 
      1. Individual with a first-degree relative diagnosed with 100 or more adenomas prior to age 40 years:
         1. Colonoscopy beginning at an age no less than 10 years; (23) and
         2. Every 1 year until age 24 years; (23) and
         3. Every 2 years from age 24 to 34 years; (23) and
         4. Every 3 years from age 34 to 44 years; (23) and
         5. No less than every 3 years thereafter. (23)
            ​​​​​​​or
      2. Individual with a first-degree relative diagnosed with more than 10 but less than 100 adenomas, colonoscopy is appropriate no less than every 3 years beginning at the same age as the youngest diagnosis of polyposis in the family, if uncomplicated by cancer or by age 40, whichever is earliest. If multiple polyps found, then colonoscopy no less than every year depending on the type, number and size of polyps. (23) or
      3. Individual with a first-degree relative diagnosed with more than 100 adenomas at age 40 or older, colonoscopy is appropriate no less than every 2 years, starting at age 40 years if uncomplicated by cancer. If multiple polyps found, then colonoscopy no less than every year depending on the type, number and size of polyps. (23)

Not Medically Necessary:
Other indications for screening or surveillance colonoscopy, not listed above, are considered not medically necessary.

Diagnostic Colonoscopy

Medically Necessary:

1. Diagnostic colonoscopy is indicated for the evaluation of any of the following:
   1. An abnormality on barium enema or other imaging study that is likely to be clinically significant (filling defect, stricture); (3) or
   2. Unexplained gastrointestinal tract bleeding such as: (3) 
      1. Hematochezia; (3) or
      2. Melena after an UGI tract source has been excluded; (3) or
      3. Presence of fecal occult blood; (3) or
      4. Unexplained iron deficiency anemia; (3)
         ​​​​​​​or
   3. A suspicion of inflammatory bowel disease, which may be manifested by abdominal pain, fever, diarrhea, bloody diarrhea, elevated erythrocyte sedimentation rate, etc.; or
   4. Clinically significant diarrhea of unexplained origin after other appropriate work up; (3) or
   5. A metastatic adenocarcinoma of unknown primary origin when colon cancer is suspected; or
   6. Intraoperative identification of a lesion not apparent at surgery (for example, polypectomy site, location of a bleeding site). (3) or
   7. Diverticulitis following resolution of a complicated episode or after a first episode of uncomplicated diverticulitis when a high-quality colonoscopy has not been performed recently (within 1 year). (12; 25; 27)

Not Medically Necessary:

1. Other indications for diagnostic colonoscopy, not listed above are considered not medically necessary, including but not limited to the following:
   1. Chronic, stable irritable bowel syndrome; (3) and
   2. Chronic abdominal pain; (3) and
   3. Acute diarrhea; (3) and
   4. Routine follow-up of inflammatory bowel disease except for cancer surveillance in chronic ulcerative colitis and Crohn's colitis; (3) and
   5. Upper GI tract bleeding or melena with a demonstrated upper GI source. (3)

Therapeutic Colonoscopy

Medically Necessary:

1. Therapeutic colonoscopy is generally indicated for any of the following:
   1. Removal of foreign body; (3) or
   2. Balloon dilation of stenotic lesions (for example, anastomotic strictures); (3) or
   3. Excision of colonic polyps; (3) or
   4. Decompression of sigmoid volvulus or an acute nontoxic megacolon; (3) or
   5. Palliative treatment of stenosing or bleeding neoplasms (for example, laser, electrocoagulation, stenting); (3) or
   6. Treatment of bleeding from such lesions as vascular malformation, ulceration, neoplasia, and polypectomy site (for example, electrocoagulation, heater probe, laser or injection therapy); (3) or
   7. Pre-operative "marking" for localization of a lesion. (3)

Not Medically Necessary:
​​​​​​​Other indications for therapeutic colonoscopy, not listed above are considered not medically necessary.

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:

When services are Not Medically Necessary:
For the procedure codes listed above when criteria are not met or for situations designated in the Clinical Indications section as not medically necessary.

Screening, surveillance and diagnostic indications for colonoscopy are based on guidelines from a variety of specialty societies and government organizations. The source for each of the indications listed above is indicated by the referenced citation.

Generally speaking, screening refers to an effort or program which is used to detect a condition in an asymptomatic individual so that early detection and treatment can be provided for those who test positive for the condition. Surveillance refers to the systematic identification and evaluation of individuals considered to be at increased risk for the occurrence or recurrence of a condition or disease (for example; colorectal cancer or adenomatous polyps. Diagnostic testing is typically done to confirm or rule out a condition in an individual who is symptomatic or who, for some other reason, is believed to have a specific condition.

Several organizations have published recommendations for colorectal cancer screening and provided guidance on when colorectal cancer screening should be initiated. The U.S. Multi-Society Task Force of Colorectal Cancer (USMSTF), which represents the American College of Gastroenterology, the American Gastroenterological Association, and The American Society for Gastrointestinal Endoscopy recommends that African Americans at average risk for colorectal cancer begin screening at 45 years of age because of an increased incidence of colorectal cancer in this population (Rex, 2018). The collaborative guideline developed by the American Cancer Society, US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology as well as the USMSTF on Colorectal Cancer recommends that individuals at average risk for the development of colorectal cancer begin screening at 50 years of age (Levin, 2008, Rex, 2017). Similarly, the National Comprehensive Cancer Network (NCCN) guidelines on colorectal cancer screening recommend that colorectal cancer screening of average-risk individuals begin at age 45 years (NCCN, 2021).

In 2018, the American Cancer Society (ACS) included several recommendations regarding colorectal cancer screening. For individuals at average risk, the society issued a “strong recommendation” that screening being at age 50 using one of several screening techniques: colonoscopy, sigmoidoscopy, CT colonography, multi-target stool DNA testing, fecal immunochemical testing or high-sensitivity guaiac-based stool testing. The “strong recommendation” signifies that “benefits of adherence to the intervention outweigh the undesirable effects and that most patients would choose the intervention”. The society also recommended that individuals considered to be at average risk for colorectal cancer should begin screening at age 45 years. However, this was a “qualified recommendation” indicating that “there is clear evidence of benefit (or harm) but less certainty either about the balance of benefits and harms or about patients’ values and preferences, which could lead to different individual decisions”. In support of its “qualified recommendation”, the ACS cites SEER (Surveillance, Epidemiology, and End Results) data which demonstrated a 22% relative increase (from 5.9 to 7.2 cases per 100,000 person-years) in the incidence of colorectal cancer between 2000 and 2013 for individuals between 40 to 49 years of age. However, other factors such as environmental influences, including but not limited to diet, and rising obesity rates, may have played a part in the increase in colorectal cancer in individuals between 45 to 49 years of age. Also, while it may be reasonable to assume that screening individuals younger than the age of 50 will produce similar results as screening individuals older than 50 years of age for colorectal cancer, the ACS recommendations did not provide any direct evidence of this assertion. Instead, the ACS recommendations were based on modeling studies on the natural history of colorectal neoplasia and the performance of colorectal screening. The authors of the ACS guidelines acknowledge that some assumptions must be made in order for the guidelines to improve population health. Some of these assumptions are that screening tests are as effective in younger individuals as in older individuals, that there will be 100% adherence to the screening recommendations (Wolf, 2018). 

In response the to 2018 ACS recommendation that colorectal cancer (CRC) screening be initiated in average risk individuals beginning at age 45 years, the USMSTF released an updated statement on colorectal cancer screening. In the updated statement the USMSTF maintained its position that colorectal cancer screening for average-risk persons begin at age 45 years in African Americans and at age 50 years in other groups. In support of these recommendations, the USMSTF also stated that:

Evidence from screening studies to support lowering the screening age is very limited at this time. Based on the modeling study used to support the ACS recommendation, the MSTF recognizes that lowering the screening age to 45 may improve early detection and prevention of CRC. The MSTF expects the new ACS recommendation to stimulate investigation that will clarify the benefits and risks of earlier screening.

As the MSTF has previously noted and discussed, rates of colorectal cancer are increasing in Americans down to age 20 years. Beginning screening at 45 years addresses only part of the increasing risk of colorectal cancer in young persons. For all persons under 50 years, it remains critical to promptly assess symptoms consistent with colorectal cancer. In particular, rectal bleeding and unexplained iron deficiency anemia have substantial predictive value for colorectal cancer and should be thoroughly evaluated (USMSTF 2018) 

The United States Preventive Services Task Force (USPSTF, 2021) guidelines on screening for colorectal cancer are unique in that they provide age-based guidance on when routine colonoscopy screening should be initiated and terminated. The updated USPSTF recommendations state that screening colonoscopy begin at age 45 years and continue to age 75 years. This is a change from the prior version, which indicated the lower threshold for screening colonoscopy as 50 years of age. The update is based on emerging evidence that colorectal cancer cases in persons younger than age 50 years have been slowly increasing (for reasons that are not entirely understood). According to the USPSTF, the number of individuals diagnosed with colorectal cancer at age 45 years today is similar to the number of individuals diagnosed with colorectal cancer at age 50 years in 1992. As part of the USPSTF review, an updated modelling study was commissioned to explore the benefits and harms of colorectal cancer screening in adults younger than 50 years. According to the analysis, lowering the age of screening from 50 to 45 years results in approximately 2 to 3 additional cases and 1 additional death due to colorectal cancer being averted per 1,000 adults screened. The harms of screening, generally resulting from colonoscopy (such as bleeding and bowel perforation), either as the screening test or as follow-up for positive findings detected by other screening tests, have not been carefully evaluated in younger individuals, but are estimated by the USPSTF to be “small”. For individuals 76 to 85 years of age, the USPSTF concluded that the benefits of screening for colorectal cancer diminish while the risk of experiencing serious associated harms increase. Therefore, the decision to screen for colorectal cancer in individuals between 76 and 85 years of age “should be an individual one, taking into account the patient’s overall health and prior screening history”. For this group, the USPSTF has indicated that “screening would be most appropriate among adults who (1) are healthy enough to undergo treatment if colorectal cancer is detected and (2) do not have comorbid conditions that would significantly limit their life expectancy”. The USPSTF recommends against the use of colorectal cancer screening in adults 85 years of age or older (USPSTF, 2016).

Colonoscopy is considered the gold standard for colon cancer surveillance. Surveillance intervals (which provide guidance on how frequently a colonoscopy should be repeated), are based upon the individual's risk factors (for example, the individual’s personal medical history, family history of colorectal cancer and the results of earlier colonoscopies). Surveillance with earlier and more frequent colonoscopy is recommended for individuals who are at increased risk for colorectal cancer.

Due to advances in next-generation sequencing (NGS) technology, multigene tests which simultaneously analyze a set of genes that are associated with a specific family cancer phenotype or multiple phenotypes are being explored as a means to create colonoscopy surveillance recommendations. With regards to using multigene testing to develop colonoscopy surveillance recommendations, the NCCN has indicated it “recognizes that data to support the surveillance recommendations for these particular genes are evolving at this time” and that “caution should be used when implementing final colonoscopy surveillance regimens in context of patient preferences and new knowledge that may emerge” (NCCN, Genetic/Familial High-Risk Assessment Colorectal, 2023).

1. Agrawal S, Bhupinderjit A, Bhutani MS, et al. Colorectal cancer in African Americans. Am J Gastroenterol. 2005; 100 (3):515-523.
2. American Society for Gastrointestinal Endoscopy. ASGE Guideline. Colorectal cancer screening and surveillance (2006). Gastrointest Endosc. 2006; 63(4):546-557.
3. American Society for Gastrointestinal Endoscopy ASGE Standards of Practice Committee. Appropriate use of gastrointestinal endoscopy. Gastrointest Endosc. 2012; 75(6):1127-1131.
4. Cairns SR, Scholefield JH, Steele RJ, et al. Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002). Gut. 2010; 59(5):666-668.
5. Centers for Medicare and Medicaid Services. National coverage determination for colorectal cancer screening tests. NCD #210.3. Effective May 12, 2009. Available at: https://www.cms.gov/. Accessed on July 18, 2022.
6. Chazouillères O, Potier P, Bouzbib C, et al. Non-invasive diagnosis and follow-up of primary sclerosing cholangitis. Clin Res Hepatol Gastroenterol. 2022; 46(1):101775.
7. DuBose J, Seehusen DA. Diagnosis and initial management of acute colonic diverticulitis. Am Fam Physician. 2021; 104(2):195-197.
8. Farraye FA, Odze RD, Eaden J, et al.; American Gastroenterological Association (AGA). AGA medical position statement on the diagnosis and management of colorectal neoplasia in inflammatory bowel disease. Gastroenterology. 2010; 138(2):738-745.
9. Gerson LB, Fidler JL, Cave DR, Leighton JA. ACG clinical guideline: diagnosis and management of small bowel bleeding. Am J Gastroenterol. 2015; 110(9):1265-1287.
10. Giardiello FM, Allen JI, Axilbund JE, et al. Guidelines on genetic evaluation and management of Lynch syndrome: a consensus statement by the US Multi-society Task Force on colorectal cancer. Am J Gastroenterol. 2014; 109(8):1159-1179.
11. Gupta S, Lieberman D, Anderson JC, et al. Recommendations for follow-up after colonoscopy and polypectomy: A consensus update by the US Multi-Society Task Force on Colorectal Cancer. Am J Gastroenterol. 2020; 115(3):415-434.
12. Hall J, Hardiman K, Lee S, et al. Prepared on behalf of the Clinical Practice Guidelines Committee of the American Society of Colon and Rectal Surgeons. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the treatment of left-sided colonic diverticulitis. Dis Colon Rectum. 2020; 63(6):728-747.
13. Hardiman KM, Felder SI, Friedman G, et al; Prepared on behalf of the Clinical Practice Guidelines Committee of the American Society of Colon and Rectal Surgeons. The American Society of Colon and Rectal Surgeons clinical practice guidelines for the surveillance and survivorship care of patients after curative treatment of colon and rectal cancer. Dis Colon Rectum. 2021; 64(5):517-533
14. Hassan C, Quintero E, Dumonceau. Post-polypectomy colonoscopy surveillance: European Society of Gastrointestinal Endoscopy (ESGE) Guideline. Endoscopy. 2013; 45(10):842-864.
15. Kahi CJ, Boland CR, Dominitz JA, et al. Colonoscopy surveillance after colorectal cancer resection: recommendations of the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2016; 150(3):758-768.
16. Keswani RN, Crockett SD, Calderwood AH. AGA Clinical practice update on strategies to improve quality of screening and surveillance colonoscopy: Expert review. Gastroenterology. 2021; 161(2):701-711.
17. Laine L, Kaltenbach T, Barkun A, et al; SCENIC Guideline Development Panel. SCENIC international consensus statement on surveillance and management of dysplasia in inflammatory bowel disease. Gastrointest Endosc. 2015; 81(3):489-501.
18. Levin B, Lieberman DA, McFarland B, et al. Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. CA Cancer J Clin. 2008; 58(3):130-160.
19. Lieberman DA, Rex DK, Winawer SJ, et al. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2012; 143(3):844-857.
20. Murthy SK, Feuerstein JD, Nguyen GC, Velayos FS. AGA Clinical practice update on endoscopic surveillance and management of colorectal dysplasia in inflammatory bowel diseases: Expert review. Gastroenterology. 2021; 161(3):1043-1051.
21. NCCN Clinical Practice Guidelines in Oncology™© 2022. National Comprehensive Cancer Network, Inc. Colon Cancer V1.2022. Revised February 25, 2022. For additional information visit the NCCN website: http://www.nccn.org/. Accessed on July 18, 2022.
22. NCCN Clinical Practice Guidelines in Oncology™© 2023. National Comprehensive Cancer Network, Inc. Colorectal Cancer Screening V1.2023. Revised May 17, 2023. For additional information visit the NCCN website: http://www.nccn.org/. Accessed on August 1, 2023.
23. NCCN Clinical Practice Guidelines in Oncology™© 2023. National Comprehensive Cancer Network, Inc. Genetic/Familial High Risk Assessment. Colorectal (V1.2023). Revised May 30, 2023. For additional information visit the NCCN website: http://www.nccn.org/. Accessed on August 1, 2023.
24. Patel SG, May FP, Anderson JC, et al Updates on age to start and stop colorectal cancer screening: Recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2022; 162(1):285-299.
25. Peery AF, Shaukat A, Strate LL. AGA Clinical Practice Update on Medical Management of Colonic Diverticulitis: Expert Review. Gastroenterology. 2021; 160(3):906-911.
26. Peterse EFP, Meester RGS, Siegel RL, et al. The impact of the rising colorectal cancer incidence in young adults on the optimal age to start screening: microsimulation analysis I to inform the American Cancer Society Colorectal Cancer Screening Guideline. Cancer. 2018; 124(14):2964-2973.
27. Qaseem A, Etxeandia-Ikobaltzeta I, Lin JS, et al. Clinical Guidelines Committee of the American College of Physicians. Colonoscopy for diagnostic evaluation and interventions to prevent recurrence after acute left-sided volonic diverticulitis: A clinical guideline from the American College of Physicians. Ann Intern Med. 2022; 175(3):416-431.
28. Rex DK, Ahnen DJ, Baron JA, et al. Serrated lesions of the colorectum: review and recommendations from an expert panel. Am J Gastroenterol. 2012; 107(9):1315-1329.
29. Rex DK, Boland CR, Dominitz JA, et al. Colorectal cancer screening: recommendations for physicians and patients from the U.S. Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2017; 153(1):307-323.
30. Rex DK, Johnson DA, Anderson JC, et al. American College of Gastroenterology guidelines for colorectal cancer screening. Gastroenterology. 2008; 134(5):1570-1595. 
31. Rex DK, Kahi CJ, Levin B, et al. Guidelines for colonoscopy surveillance after cancer resection: a consensus update by the American Cancer Society and US Multi-Society Task Force on Colorectal Cancer. CA Cancer J Clin. 2006; 56(3):160-167. 
32. Sartelli M, Weber DG, Kluger Y. 2020 update of the WSES guidelines for the management of acute colonic diverticulitis in the emergency setting. World J Emerg Surg. 2020; 15(1):32.
33. Scott MW, Layton MC, Teer BN, Domagalski JE. Colorectal cancer screening and surveillance. Am Fam Physician. 2015; 91(2):93-100.
34. Shergill AK, Farraye FA. Toward a consensus on endoscopic surveillance of patients with colonic inflammatory bowel disease. Gastrointest Endosc Clin N Am. 2014; 24(3):469-481.
35. Steele SR, Chang GJ, Hendren S, et al.; Clinical Practice Guidelines Committee of the American Society of Colon and Rectal Surgeons. Practice guideline for the surveillance of patients after curative treatment of colon and rectal cancer. Dis Colon Rectum. 2015; 58(8):713-725.
36. Taylor DP, Burt RW, Williams MS, et al. Population-based family history-specific risks for colorectal cancer: a constellation approach. Gastroenterology. 2010; 138(3):877-885.
37. U.S. Multisociety Task Force on Colorectal Cancer. Message to members of AGA, ACG and ASGE regarding new American Cancer Society colorectal cancer screening guidelines (June 2018). Available at: https://www.gastro.org/press-release/statement-from-the-u-s-multisociety-task-force-on-colorectal-cancer. Accessed on July 18, 2022.
38. US Preventive Services Task Force, Davidson KW, Barry MJ, Mangione CM, et al. Screening for Colorectal Cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2021; 325(19):1965-1977.
39. Winawer S, Fletcher R, Rex D, et al. Colorectal cancer screening and surveillance: clinical guidelines and rationale-Update based on new evidence. Gastroenterology. 2003; 124(2):544-560.
40. Wolf AMD, Fontham ETH, Church TR, et al. Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society. CA Cancer J Clin. 2018; 68(4):250-281.
41. Worthington DV. American Academy of Family Physicians (AAFP) position paper: colonoscopy: procedural skills. Am Fam Physician. 2000; 62(5):1177-1182.
42. Hadjiliadis D, Khoruts A, Zauber AG, et al. Cystic fibrosis colorectal cancer screening consensus recommendations. Gastroenterology 2018; 154:736-745 e714.
43. Maisonneuve P, FitzSimmons SC, Neglia JP, et al. Cancer risk in nontransplanted and transplanted cystic fibrosis patients: a 10-year study. J Natl Cancer Inst. 2003; 95(5):381-387.
44. Children’s Oncology Group. Long-Term Follow-up Guidelines for survivors of childhood, adolescent, and young adult cancers, Version 5.0. Monrovia, CA. Children’s Oncology Group; 2018. Available at: www.survivorshipguidelines.org.

Colonoscopy
Colorectal Cancer Screening